Wounded-nucleon model with realistic nucleon-nucleon collision profile and observables in relativistic heavy-ion collisions

Abstract

We investigate the influence of the nucleon-nucleon collision profile (probability of interaction as a function of the nucleon-nucleon impact parameter) in the wounded-nucleon model and its extensions on several observables measured in relativistic heavy-ion collisions. We find that the participant eccentricity coefficient, ${\ensuremath{\epsilon}}^{*}$, as well as the higher harmonic coefficients, ${\ensuremath{\epsilon}}_{n}^{*}$, are reduced by 10--20$%$ for midperipheral collisions when the realistic (Gaussian) profile is used, as compared to the case with the commonly used hard-sphere profile. Similarly, the multiplicity fluctuations, treated as the function of the number of wounded nucleons in one of the colliding nuclei, are reduced by 10--20$%$. This demonstrates that the Glauber Monte Carlo codes should necessarily use the realistic nucleon-nucleon collision profile in precision studies of these observables. Our study is relevant for hydrodynamic calculations which use the Glauber-model initial conditions. The Gaussian collision profile is built-in in glissando.